无返回值 map_delete( 映射 m, 混合 element );

　 范例:
　

　 mapping names;

　 names = ([]);
　 names["truilkan"] = "john";
　 names["wayfarer"] = "erik";
　 names["jacques"] = "dwayne";

　 map_delete(names,"truilkan");

　 (["wayfarer" : "erik", "jacques" : "dwayne"])